1. Field of the Invention
The present invention relates to a two-dimensional (2D) and three-dimensional (3D) switchable display device, and more particularly, to a 2D and 3D switchable display device that includes an embedded polarization activated microlens in order to omit at least one glass substrate (such as transparent substrate) which is used to cover the polarization activated microlens.
2. Description of the Prior Art
The principle of stereoscopic display technique is to make the left eye and right eye of the viewer receive different images separately. These different images separately received by the left eye and right eye will be analyzed by human brain so that the viewer can perceive the depth of image. Consequently, stereoscopic vision is generated.
At present, the stereoscopic display devices can be mainly classified into two types: time-sequential type and spatial-multiplexed type. The time-sequential type stereoscopic display device provides left-eye image for left eye and right-eye image for right eye in turn in a scanning manner. When viewing the display device, the viewer must wear a pair of shutter glasses. The pair of shutter glasses allows the left eye of the viewer to see the left-eye image but blocks the right eye of the viewer to see the left-eye image when the display device display the left-eye image, and allows the right eye of the viewer to see the right-eye image but blocks the left eye of the viewer to see the right-eye image when the display device display the right-eye image. Accordingly, stereoscopic display effect can be obtained. The spatial-multiplexed type stereoscopic display device includes a parallax barrier type stereoscopic display device. The parallax barrier type stereoscopic display device uses a parallax barrier disposed in front of the display device. When observing the display device, the left eye and the right eye of the viewer, due to their different viewing angle with respect to the parallax barrier, will only see the left-eye image and the right-eye image separately.
The conventional stereoscopic display devices, however, face some problems or disadvantages in their applications. For example, the viewer of the time-sequential type stereoscopic display device must wear a pair of shutter glasses, which causes inconvenience in use. The spatial-multiplexed type stereoscopic display device has limitation in the distance between the viewer and the display device when observing. Specifically, the viewer can only obtain the stereoscopic images in some particular distance range. In addition, when the spatial-multiplexed type stereoscopic display device is applied in high resolution mobile phone or other high resolution portable electronic products, in which the optimal 3D display viewing distance is shorter, the glass substrate between the parallax barrier and the display device has to be reduced so that the viewing distance can be reduced to meet the optimal 3D display viewing distance. However, the thickness reduction of the glass substrate is restricted to the limitation of glass process, and the structural strength of the glass substrate will be affected when reducing the thickness of the glass substrate. Therefore, to shorten the viewing distance of the stereoscopic display device applied in high resolution portable electronic product is an important issue to be solved.